Leeds - Liverpool Canal

Also within

West Yorkshire County

Condition (Natural England)

Habitats

Fast flowing river and stream

Birds & fish recorded

Fish

Description

Description This section of the Leeds Liverpool canal extends from close to Leeds city centre ‘upstream’ to a point just north of the village of Calverley. It rises from 50 metres to 60 metres above the sea level and closely follows the river Aire. Whereas the underlying rocks of the Aire valley at this point are the Coal Measures the water quality and biological character of the canal are largely determined by the nature of the water supply and materials used in its construction. Low levels of pollution and turbidity combined with alkaline water supply and a base rich puddle clay substrate provide a unique aquatic habitat in this part of West Yorkshire. The Leeds Liverpool canal is the best example of a slow flowing fresh water habitat in the county. There is a rich aquatic flora including eight species of pondweed Potamogeton spp one of which, Potamogeton trichoides, is nationally scarce and known to be declining. Ridged hornwort Ceratophyllum demersum a species more typical of still rather than moving water occurs and there is an abundance of arrowhead Sagittaria sagittifolia. Both species have a very restricted distribution in the county. The canal supports a characteristic range of emergent vegetation but two notable species occur here; the flowering rush Butomus umbellatus and sweet flag Acorus calamus, both of which are uncommon in West Yorkshire and are here close to the northern limits of their range in great Britain. The aquatic moss Fontinalis antipyretica is widely distributed and in places abundant and the brown alga Bangia atropurpurea occurs here close to its northernmost limits in this country. A representative aquatic fauna occurs with good populations of fish, including pike, roach and gudgeon and both common frog and common toad breed here. There are an abundance of invertebrates with molluscs being very well represented and including both gastropods such as Peregriana peregra and bivalves such as Sphaerium rivicola. The number and individual size of freshwater sponges Spongilla spp. and horse leech Haemopsis spp. are a particularly interesting feature.

Species mentioned

Plant communities